Results

The intestinal microbiota in gastric cancer patients was characterized by increased species richness, decreased butyrate-producing bacteria, and the enrichment of other symbiotic bacteria, especially Lactobacillus, Escherichia, and Klebsiella. Lactobacillus and Lachnospira were key species in the network of gastric cancer-associated bacterial genera. The combination of the genera Lachnospira, Lactobacillus, Streptococcus, Veillonella, and Tyzzerella_3 showed good performance in distinguishing gastric cancer patients from healthy controls. There was no significant difference in enterotype distribution between healthy controls and gastric cancer patients. The percentage of CD3+ T cells was positively correlated with the abundance of Lactobacillus and Streptococcus, and CD3+ T cells, CD4+ T cells, and NK cells were associated with Lachnospiraceae taxa.

Conclusions

Our study revealed a dysbiotic intestinal microbiota in gastric cancer patients. The abundance of some intestinal bacterial genera was correlated with the population of peripheral immune cells.

Notes

Acknowledgments

This study was funded by the National Natural Science Foundation of China (Grant Numbers: 81272696) and the Special Foundation for Talents of Shanxi Province of China (Grant Numbers: 201705D211021). We thank AJE (www.aje.com) for its linguistic assistance during the preparation of this manuscript.

Compliance with ethical standards

Conflict of interest

All authors declare that they have no conflict of interest.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

Supplementary material

Supplementary Figure 1. Rarefaction curves of the number of OTUs versus the number of reads. The x-axis shows the number of OTUs; the y-axis shows the number of reads sampled randomly. HC, healthy control group; GC, gastric cancer group, OTUs, operational taxonomic units (TIFF 3379 kb)

Supplementary Figure 4. The top 30 differentially abundant genera of bacteria between HC and GC by Wilcoxon rank-sum test. The left panel shows the average relative abundance of bacterial genera in both groups. The right panel shows 95% confidence intervals and P values. HC, healthy control group; GC, gastric cancer group (TIFF 2955 kb)